Polar transfer switch



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Oct. 4, 1966 United States Patent O 3,277,414 POLAR TRANSFER SWITCH JackA. Piccininni, Bronx, N.Y., assignor to Bell Telephone Laboratories,Incorporated, New Yorlr, N.Y., a corporation of New York Filed Mar. 5,1964, Ser. No. 349,560 2 Claims. (Cl. 335-153) This invention relates toelectromagnetic switching devices and in particular pertains toelectromagnetic relays ofthe type in which sealed contact reed switchesmay conveniently be used.

Electromagnetic. relays employing sealed contact Switches have beendeveloped to take advantage of the low power requirements, long contactlife, and reliable switching action which can `be obtained when movingcontacts are encapsulated in a sealed vessel. Sealed contact switches ofthe reed type are particularly suitable for use in such relays and arereadily available commercially.

The conventional sealed contact reed switch comprises a pair of magneticmembers sealed in overlapping relationship within a glass tube.Functionally, such devices are of the make-break type. For example, whena magnetic flux is applied axially through a reed switch, the reeds areattracted until they close. The reeds open by springing apart when theilux is discontinued.

Although make-break switches are suicient in many applications, thereare many other applications wherein it is advantageous to open onecircuit while closing another cir-cuit. A switching device performingthis function is commonly called a transfer relay.

It is, therefore, an object of this invention to control the ilow ofelectricity between alternate paths.

It is another object of this invention to control the switching `ofelectricity between alternate paths by using seale-d contact reedswitches.

It is still another object of this invention to control the switching ofelectricity by using sealed contact reed switches and opposed iluxsources.

One feature of this invention resides in alternately `directing onemagnetic ilux emanating from a magnetic member magnetically poled in onedirection through a shunt and a sealed contact reed switch in that orderwhile concurrently directing another magnetic flux emanating from anoppositely poled magnetic member alternately through another sealedcontact reed switch and another shunt in that order by controlling thereluctance of a magnetic core common to Iboth magnetic iluxes.

According to one embodiment of this invention, a pair of remanentmagnetic members is combined in parallel with a pair of sealed contactreed switches and a magnetic core having a coil wound thereon. In oneform of the invention, one sealed contact reed switch is disposedbetween the magnetic core and a rst remanent magnetic member having anopposite magnetic pole at each end. The other sealed contact reed switchis disposed between the magnetic core and the remaining magneticremanent member. The remaining magnetic member has an opposite magneticpole at each end and is disposed with respect to the iirst remanentmagnetic member in such a manner that opposite poles on each remanentmagnetic member are adjacent.

Other objects, advantages, and novel aspects of this invention willlbecome apparent upon consideration of the following detailed descriptionin conjunction with the accompanying drawing wherein:

FIG. l is a plan view of a relay assembly constructed in accordance withthe present invention.

The embodiment illustrated in FIG. 1 comprises two magnetic members 1and 2, two sealed contact reed switches 3 and 4, and a magnetic core 5having a coil 3,277,414 Patented Oct. 4, 1966 ICC 6 wound thereon. Thecore 5 may conveniently be made from any magnetic material. A materialhaving a coercive force in the order of 5() oersted-s, however, ispreferred. The magnetic members 1 and 2 may also be conveniently madefrom any magnetic material. A material having a coercive force ofapproximately 500 oersteds, however, is preferred. In fact, either orboth of the magnetic members 1 and 2 may be replaced by any convenientsource of magnetic flux. As illustrated in FIG. l, each of the switches3 and 4 is disposed between the magnetic core 5 and one of the magneticmembers 1 and 2, respectively. Moreover, all of the cornponents of theswitch are `disposed in parallel with each other. Furthermore, eachmagnetic member 1 and 2 is magnetically poled in a direction opposite tothe other.

In the unoperated state, tlux from the magnetic members 1 and 2 travelsthrough the relay in parallel paths comprising the magnetic core 5 andthe sealed contact reed switches 3 and 4, respectively.

When the coil 6 is energized, however, the flux pattern of theunoperated state is disturbed. The flux pattern with respect to a firstmagnetic member, a first sealed contact reed switch, and the magneticcore 5 remains unchanged, but the flux pattern with respect to a secondmagnetic member, a second sealed contact reed switch, and the magneticcore 5 is rearranged because flux induced in t-he magnetic core 5opposes flux in one flux pattern and aids flux in the other.

For example, when the coil 6 is energized to produce magnetic polaritiesas illustrated in FIG. l, the reluctance of the magnetic core 5 isincreased with respect to the flux entering from the magnetic member 1.As a consequence, most of the flux from the magnetic member 1 is unableto enter the magnetic core 5 and so takes an alternate path through thesealed contact reed switch 3.

Furthermore, when the coil 6 is energized, it develops a flux in themagnetic core 5. As this ux opposes the flux from the magnetic member 1,a portion thereof is also compelled to pass through the sealed contactreed switch 3. When both fluxes pass through the sealed contact reedswitch 3 together, the switch operates. Moreover, it remains operateduntil the magnetic polarity of the magnetic core Sis changed.

On the other hand, with the coil 6 energized to pro- -duce the magneticpolarities shown in FIG. l, the state of the sealed contact reed switch4 remains unchanged. As illustrated in FIG. l, a portion of the iluxfrom the magnetic member 2 continues to `shunt the sealed contact reedswitch 4 and pass through the magnetic core 5.

If the coil 6 is merely de-energized and the magnetic core 5 is made ofa soft magnetic material, all the magnetic systems in the relay willreturn to the unoperated state. If, however, the coil 6 is energized soas to magnetically pole the magnetic core 5 in a direction opposite tothat illustrated in FIG. l, the above-described magnetic patterns willreverse themselves. It will be readily seen, therefore, that the sealedcontact reed switch 3 will open while the sealed contact reed switch 4will close.

Where, however, the coil 6 is de-energized and the magnetic core 5 isnot soft but is made of a remanent material such as remandur, themagnetic polarity of the magnetic core 5 remains substantiallyunchanged. As a result, the sealed contact reed switch 3 will remainclosed and the sealed contact reed switch 4 will remain open without thenecessity of supplying power to the coil 6 from an external source.Moreover, when the magnetic core 5 is switched from one magneticpolarity to the other, the sealed contact reed switch 4 will close andremain closed while the sealed contact reed switch 3 will open andremain open without the necessity of supplying power to the coil 6 froman external source.

Experiment has disclosed that for a current pulse in the coil 6 in theorder of 8.25 amperes, the closed contacts will open about 30microseconds after the start of the current pulse and the open contactswill initially close about 400 microseconds after the -start of thedrive pulse. Release time for the closed contacts remains about 30microseconds when the current pulse is varied from 4.8 to ll amperes;but the closure time varies from 440 to 600 microseconds for 4.8amperes, and 390 to 500 microseconds for ll .amperes From this data, itis clear that a relay in accordance with this form of the invention willinvariably produce a break-before-make switching function.

From the foregoing, it is readily apparent that various arrangements ofcomponents can be advantageously used to exploit this invention.Therefore, While certain specic embodiments have been selected fordetailed disclosure, the invention is not limited in its application tothe embodiments disclosed. As a result, the embodiment which has beendescribed should be taken as illustrative of the invention and itsapplication rather than restrictive thereof.

What is claimed is:

1. The combination comprising:

a core made of a material having a coercive force in the order of 50oersteds;

a coil wound on said core;

a iirst bar-type permanent magnet -disposed in parallel with said core;

a sealed contact reed switch disposed in parallel between said core andsaid rst permanent magnet;

a second permanent magnet disposed in parallel with said core and withits magnetic polarity reversed with respect to the polarity of said rstpermanent magnet;

and another sealed contact reed switch -disposed in parallel betweensaid second permanent magnet and said core.

2. In a switching device, the combination comprising:

a first magnetic member;

a core having a flux-generating coil wound thereon;

a rst pair of overlapping reed contacts disposed in parallel to `andbetween said first magnetic member and said core, sai-d rst pair ofoverlapping reed contacts being arranged to close when ux from said `rstmagnetic member and said coil is aiding and to open when sai-d ilux isopposing;

a second magnetic member disposed with its poles opposite to those ofsaid first magnetic member;

and a second pair of overlapping reed contacts disposed in parallel toand between said second magnetic member and said core, said second pairof overlapping reed contacts being arranged t-o close when flux fromysaid second magnetic member and said coil is aiding and to open whensaid flux is opposed.

References Cited by the Examiner UNITED STATES PATENTS 1,953,929 4/1934Droysen 20G-93 2,794,178 5/1957 Reynolds 20o-93 2,902,558 9/1959v Peek20o-87 3,184,563 5/1965 Myaft 20o-87 References Cited by the ApplicantUNITED STATES PATENTS 2,995,637 8/ 1961 Feiner. 3,002,066 9/ 1961Kethledge. 3,020,369 2/1962 Jacobson.

BERNARD A. GILHEANY, Primary Examiner.

B. DOBECK, Assistant Examiner.

1. THE COMBINATIONN COMPRISING: A CORE MADE OF A MATERIAL HAVING ACOERCIVE FORCE IN THE ORDER OF 50 OERSTEDS; A COIL WOUND ON SAID CORE; AFIRST BAR-TYPE PERMANENT MAGNETIC DISPOSED IN PARALLEL WITH SAID CORE; ASEALED CONTACT REED SWTICH DISPOSED IN PARALLEL BETWEEN SAID CORE ANDSAID FIRST PERMANENT MAGNET; A SECOND PERMANENT MAGNET DISPOSED INPARALLEL WITH SAID CORE AND WITH ITS MAGNETIC POLARITY REVERSED WITHRESPECT TO THE POLARITY OF SAID FIRST PERMANENT MAGNET; AND ANOTHERSEALED CONTACT REED SWITCH DISPOSED IN PARALLEL BETWEEN SAID SECONDPERMANENT MAGNET AND SAID CORE.